Nanocellulose has been shown to be potentially very useful for a number of technical applications in the future. The key to understanding how nanocellulose will behave in different applications is to have a thorough understanding of how the structure and interactions of nanocellulose affect its function and hence its suitability for different applications.
The research carried out at VTT relates to the whole production chain of nanocellulose – from the selection of raw materials to the development of the production process and modification of nanocellulose material according to the needs of various applications. Successful use of nanocellulose in different applications requires a profound understanding of the structural and molecular properties of nanocellulose.
VTT Technical Research Centre and Aalto University have developed a pilot-scale method to manufacture nanofibrillated cellulose film. The method enables industrial scale roll-to-roll production of the film, which is suitable for specific packaging applications, or can be used in several added value applications of printed electronics and diagnostics.
The nanocellulose films are translucent, showing no shrinkage or defects. The high smoothness of the surface provides excellent printing quality, and the densely packed structure results in a material with outstanding oxygen barrier properties. Based on their properties, the potential applications for these films are numerous, being high performance packaging, flexible displays and printable electronics, or low cost diagnostics.
The R2R film production process was developed in the public research part of the Finnish Centre for Nanocellulose Technologies (co-operation project between VTT, Aalto University and UPM company).The main part of the funding was received from Tekes.
We have contacts with all leading pulp and nanocellulose manufacturers as well as to all recognised research groups worldwide. We have served industries and customers from the forest sector, paper converting, and the chemical sector.
Unique film manufacturing method
Nanofibrillated cellulose typically binds high amount of water and forms gels with only a few per cent dry matter content. In the manufacture of the films, the removal of water and drying are challenging, so this characteristic is one bottleneck for industrial-scale manufacture.
In most cases, fibril cellulose films are manufactured through pressurised filtering, but the gel-like nature of the material makes this route difficult. In addition, the wires and membranes used for filtering may leave a so-called “mark” on the film which has a negative impact on the evenness of the surface.
With our method nanofibrillated cellulose films are manufactured by evenly coating fibril cellulose on plastic films so that the spreading and adhesion on the surface of the plastic can be controlled. The films are dried in a controlled manner by using a range of existing techniques. Thanks to the management of spreading, adhesion and drying, the films do not shrink and are completely even. The more fibrillated cellulose material is used, the more transparent films can be manufactured. The even surface of the underlying plastic surface is almost completely replicated on nanocellulose film surface.
Broad expertise in nanocellulose film manufacturing
Several metres of fibril cellulose film can be manufactured with VTT’s pilot-scale concept in Espoo. All the phases in the method can be transferred to industrial production processes and the films can be manufactured using unit operations that already exist in the industry.
We have solid expertise and pilot scale roll-to-roll manufacturing facilities/process to prepare nanocellulose films. We also have relevant characterisation tools.
Nanocellulose films can be a potential substrate in several applications of packaging industry, electronics and diagnostics.